Holder for shaping and similar tools



A. C. TWIGG.

HOLDER FOR SHAPING AND SIMILAR TOOLS.

' I APPLICATION FILED IEILZS, |920- Patented im.. 19,1920.

ARTHUR C. TWIGG, OF BIRMINGHAM, ENGLAND.

HOLDER FOB SHAPING AND SIMILAR TOOLS.

Specification of Letters Patent.

Patented Oct. 19, 1920..

Application filed February 26, 1920. Serial No. 361,479.

To all 'LU/0m t may concern.'

Be it known that l, ARTHUR CHARLES Twice, subject of the King of Great Britain, and resident of Birmingham, England, have invented certain new and useful Improvements in Holders for Shaping and birnilar Tools, of which the following is a specification.

This invention has reference to holders for shaping and similar tools, and consists in an improved tool-holder which is particularly adapted for attachment to the head of a hand-operated screw press such as shown and described in British Patent No. 122,981, granted to me May 25, 1918, so as to enable die-cutting external slotting, shaping, and like operations to be performed with a press-actuated tool instead of by the more usual method of hand-chipping with a hammer and chisel. The improved holder can, however, also be used in connection with shaping and like machines in which the head or slide has a reciprocating action.

The said holder, as adapted for attachment to the reciprocating head of a handpress, is shown in the accompanying drawing, in which Figure 1 is a side elevator of the holder, and

l? line fr.

rlhe special feature of the improved holder is that it provides, in a novel and effective manner, for what is kknown as relief action of the tool which obviates heavy drag or friction between the tool and the work during the return stroke of the former, and so preserves the cutting edge and prevents tool breakages such as are likely to occur when the tool is held rigidly in relation to the reciprocating part of the machine by which it is operated. Further features of the holder are thatit admits of the adjustment of the clearance or cutting angle of the tool when the holder 2 is a cross section on the dotted y is attached to the head or ram of a handpress or other machine, and also provides for the correct setting or adjustment of the tool to the most effective cutting position either after the said tool has been removed from the holder for regrinding, or when a new or different tool is fitted.

As will be seen from the drawing, the` hand-press tool-holder consists of two main parts, viz., a tool-housing a in which the tool Z is mounted, and a bracket c, which is adapted to be rigidly Xed to the head or slide of a press by a bolt passing through the eye c in the horizontal part c2 of the said bracket. The housing a is pivoted to the bracket by the cross bolt CZ, and carries the tool in a vertical plane at right angles to the pivot and wholly above and in front of the pivot-center, which not only provides for an effectiverelief action when the tool commences its return stroke, but also enables the' tool to be set up or adjusted to a position in the housing wherein the cutting edge is exactly in line with the pivot center (as indicated in the dotted line e in Fig. l) whichis essential for avoiding breakage or dulling of the tool point on the solid shoulders that are produced on the work where the cut finishes.

A spring f is arranged between an abutment 03 on the bracket and a seating f1 in the lower part of the housing so that it exerts an outward thrust against the said housing from a point below and inward of the pivot center, and so tends to tilt the upper part of the housing and the tool toward the head or slide (indicated at g) of the operating machine. The spring is adjustable by the screw n.

The rear upper part of the housing is furnished with an adjustable stop-screw e' which is taken against the face of the head g by the thrust of the spring f at the end of the return stroke of the operatingmachine. This stop is adjustable inward or outward for altering the normal angular position of the housing in relation to the bracket and thus setting the tool at a greater or less angie from the vertical according to the clearance angle required.

The tool o is carried in a socket a in the front of the housing and is adjustable by a set screw j that bears against the upper end of the said tool as shown in Fig. l so that, when fitting a tool in the holder or when the tool is replaced therein after grinding, the same can be readily and accurately adjusted into the position wherein its cutting edge Zi is in horizontal alinement with the center of the pivot-bolt. After'such adjustment of the tool has been arrived at, the latter is rigidly fixed in the housing by tightening up the clamping bolt 7c (see Fig. 2).

A holder such as above described imparts a solid drive on the tool throughout the cutis finished and the edge of the tool is against the shoulder at the bottom of the surface that is being Worked upon) the return stroke of the holder is commenced, the spring is put under compression so that during such return stroke, the tool is yicldingly held against the face of the Work bythe play of the spring upon the housing, and the dead drag or friction is avoided.

When, at the completion of the return stroke, the edge of the tool clears the work, the expansion of the spring displaces the housing and tool to an extent sufficient to take the stop@ into contact withl the face of the machine-head g, so as to position the said tool at the correct angle before the next cutting stroke is started.

The improved tool-holder can bey readily adapted' for use in shaping, slotting and like machines in which the actuating head or slide has a horizontal reciprocating action, in which case the bracket fixing is arranged to support the tool housing horizontally and the tool itself is mounted in a horizontal poangular -movement t0 the housing about the pivot of the latter for ,setting the edge of the tool into line with the pivot center on which the said housing is movable when under the influence of the relief action spring during the return stroke` of the holder.'

Having described my invention, whatv i claim and desire to secure by Letters Patent is A relief-action tool holder comprising :i bracket fixing for attachment to the of the actuating machine, a tool housing pivoted to bracket and adapted to carry the tool above and in front of the pivot center, a relief spring acting on'the back of the housing at a point below the pivot, an adjustable stop for determining the cutting angle of the tool,'and a tool-adjusting screw for setting the cutting edge of the tool into alinement with the center of the housing pivot, substantially as herein described.

Signed at Birmingham, England, this 6th day ofA February, A. D. 1920. Y

A. C. TVIG i.

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